England 130 for 2 (Buttler 68*, Roy 36) beat Sri Lanka 129 for 7 (Shanaka 50, Perera 30, Rashid 2-17, Curran 2-25) by eight wickets
Cardiff: Jos Buttler's unbeaten 68 helped England to a comfortable eight-wicket win over Sri Lanka in the first Twenty20 in Cardiff.
Chasing 130, Buttler and Jason Roy shared an 86-run opening stand before Roy fell for 36 to a stunning catch from Danushka Gunathilaka.
However, Buttler anchored England as they won with 17 balls to spare.
Sri Lanka earlier struggled to 129-7, with Dasun Shanaka making 50 and Adil Rashid taking 2-17 and Sam Curran 2-35.
The second game of the three-match series takes place on the same pitch at Sophia Gardens on Thursday.
Captain Eoin Morgan said before the match that this series would give players the chance to push for selection for the T20 World Cup starting in October.
While Chris Woakes, playing his first international T20 since 2015, bowled tidily, it was Rashid who stood out for the hosts.
He did not concede a boundary in his four-over spell and his variations forced both Kusal Perera and Wanindu Hasaranga to hole out to Chris Jordan at long-on.
Despite opting to bat first, Sri Lanka never got going on a slow surface. They went 35 balls without a boundary after losing Danushka Gunathilaka in the fifth over and struggled to put any pressure on England's fielders with their running.
It was only Shanaka's acceleration, moving from 26 off 33 balls to a 43-ball half-century, that gave them a decent total.
In response, Buttler moved to his ninth half-century in 20 innings as an opener, in a performance described as a "masterclass" by Morgan.
After playing carefully early on, Buttler unleashed, hitting eight fours and one six, including consecutive boundaries off Isuru Udana.
Roy struggled for rhythm and his innings was brought to an end by a superb catch by Gunathilaka, leaping full length to his left at mid-off.
Dawid Malan also found the pitch difficult to read, toiling to seven off 13 balls before he was bowled by Udana, but Buttler saw England home with ease.